Lumacaftor is developed by Vertex and combined with Ivacaftor for the treatment of cystic fibrosis (CF) in patients aged 12 years and older who have the F508del mutation in the cystic fibrosis transmembrane conductance regulator (CFTR). Combination of Lumacaftor/Ivacaftor was approved in the United States on Jul. 2, 2015 under the brand name Orkambi. The chemical name of Lumacaftor is 3-(6-(1-(2,2-difluorobenzo [d] [1,3] dioxol-5-yl) cyclopropanecarboxamido)-3-methylpyridin-2-yl) benzoic acid, and the structure is shown as formula (I):

CN101910156A disclosed crystalline Form I of Lumacaftor and Form I has an X-ray powder diffraction pattern comprising the following 2theta values measured using CuKα radiation: 15.2-15.6°, 16.1-16.5°, 14.6-15.0°, 17.6-18.0° and 14.3-14.7°. Form I can be obtained by suspending the hydrochloride of compound of formula (I) in water. Additionally, the patent disclosed another method to obtain Form I through intermediate of compound of formula (I). The preparation method of the new crystalline form in present disclosure is directly obtained from compound of formula (I) free form, which is different from that of Form I in CN101910156A.
As is known to the skilled in the art, the presence of new solid polymorphic forms of a known chemical substance is unpredictable. The existence of the polymorphic compound or the number of the polymorphic forms is also unpredictable. In addition, it is also unpredictable under what conditions to obtain a specific form, and how are the characteristics of the polymorphic form. Since the properties (e.g., solubility, stability) of each polymorph of the compound cause the different performance on drug's application and storage, it is necessary to study all solid forms, including all polymorphic forms to provide drugs with improved stability or solubility.
CN101910156A disclosed crystalline Form I but there is no description on the characteristics such as stability and solubility. The inventor of the present disclosure found a new crystalline form of Lumacaftor with better characteristics. The crystalline form in present disclosure has good stability and higher solubility than prior art. It has unexpected technical effect and great value for further development of the drug.